1. Field of the Invention
The present invention relates to optical communication equipment and, more specifically, to optical sources used in optical communication systems.
2. Description of the Related Art
Modern optical communication systems transmit information between communication nodes using wavelength division multiplexed (WDM) signals. The generation of WDM signals in such systems relies on light sources capable of producing electromagnetic radiation at appropriate multiple wavelengths (frequencies). One such light source is a semiconductor mode-locked (ML) laser, which owes its utility to its relatively small size, high power, low noise, and low cost. However, a general problem with prior-art semiconductor ML lasers is that a typical range of wavelengths (spectral bandwidth) provided by such lasers is relatively narrow, e.g., about 20 nm.